Relationship between the sensitivity and beam splitting ratio, conversion efficiency, and local oscillator power in balanced detection

Abstract

Balanced detection, which is becoming increasingly essential for wireless communication and optical fiber communication, has been extensively studied in recent years. However, the relationships between the sensitivity and the other parameters have not yet been comprehensively ascertained. In this work, the relationship between the sensitivity and the local oscillator power P l o , consistency parameter Δ α , and beam splitting ratio ε in balanced detection is explored through numerical and communication system simulations. If ε decreases, the sensitivity increases, and the corresponding P l o decreases. With the increase or decrease in Δ α , ε corresponding to the minimum sensitivity shifts toward the right or left, respectively. This shift increases with the increase in the absolute value of Δ α , and the minimum value of the sensitivity increases. When the absolute values of Δ α are equal, their curves are almost symmetrical. As ε approaches 0.5, the tolerable maximum of P l o becomes higher. At any instant, the average value of the quantum efficiency of the two photodiodes is more critical than the maximum quantum efficiency and balance. This work facilitates thorough understanding of the sensitivity of balanced detection, which can be beneficial for future optical communication design.